Old anime looks different, but sadly I can't tell you exactly why
One of the things I did this year was watch some older anime; the Crusher Joe movie (and one OVA) from 1983, and Iria: Zeiram the Animation from 1994. One of the things that struck me about both of these, especially Iria, is how they looked and felt clearly different from modern anime. This is more than a difference in the look of the art, the style of people's outfits and hair, and the kind of settings; it was also something distinctly different in how each work looked in a broader sense.
(Crusher Joe is very distinctly an 80s work; consider this scene, for example.)
Some of this is in the use of 'light gleam' effects that aren't used as much (or in the same way) any more, such as the bright beam blasts near the start of this Crusher Joe scene. My understanding is that this classical effect in cell-based animation is done by leaving sections of the cell either completely transparent or translucent (with coloured film behind them) and then letting the backlight from the rostrum camera show through the cells. This gives a vivid glow in a relatively simple to animate way (and it's a glow that can spread outside the lit up area).
Crusher Joe is a film and was clearly well-produced even at the time. Perhaps as a result, its 'old anime' feel is mostly confined to how things are drawn; there's an old fashioned feel to both the foreground and the background rocks along the roadway in this segment or the hand-drawn digital display in this scene at about four seconds in. But even then there's something that feels distinctly old about how the movie simply rotates the cell of Alfin in her cockpit starting at four seconds in this scene. I can see how this would be an easy effect to do in a cell-based world; you draw the cell a bit larger and then just rotate the rostrum camera when you film the frames.
A case with a deeper feel of difference is the opening for Dirty Pair: Project Eden here (or on YouTube with sound). This is from 1986 and undeniably beautiful, but at the same time it strikes me as something that you wouldn't see today and that looks definitely old fashioned (it too has a bunch of 'light gleam' effects). I suspect that a lot of the unusual feel is the use of silhouettes and of echoed movement (for example at 51 seconds). But I don't know if this was easier or harder in days of drawn and filmed cell animation.
Iria: Zeiram the Animation is an OVA and thus probably had less production resources that the Crusher Joe movie, which I suspect makes it lean more heavily on things that were easy to do in the cell animation days. Looking at its opening, I see things that stand out to me at various points; there are repeated inset frames of animation (at 25 seconds), 'light gleam' streaks (at 29 seconds), rotating cells (33 seconds), distinctly overlaid foreground snow (at 1 minute), echoed frames of animation (at 1:26), and then it just runs some earlier animation backward starting at 1:29 or so. Beyond that, there's a lot of scenes in the actual show that feel to me like they wouldn't be done today.
(For example, it feels like Iria uses a lot more held frames and panned frames than is normal today.)
However, this is where I run into the limits of my ability to analyze and explain animation this way. All of what I've talked about so far is basically hand waving and theorizing. I know both Crusher Joe and especially Iria feel distinctly different but I can't really tell you why, with chapter and verse and technical details. All I can do is look for some obvious things that feel unusual, when really it was a much more pervasive thing that ran all through my watching of both works and it didn't feel directly related to the different look of hand painted cell animation. I'm pretty sure that many shots were composed and designed differently than they would be today, but I can't tell you how (or why); at best I can theorize about obvious things, like rotating cells or those 'light gleam' effects and how they give the frames an overall glow.
This frustrates me a bit. I'd like to be able to understand this myself and be able to explain it, instead of waving my hands and doing what feels like nit-picking. Instead, it's another limitation I've discovered on my ability to analyze things.
(This is part of the 12 Days of Anime for 2017.)
Sidebar: The other way Iria looks different
As an SF show, Iria takes place in a different world (a couple of them, actually). It's clear that the show has worked hard to create a coherent yet decidedly different cultural feel for its setting, where the clothes, the buildings, the vehicles, and so on are all pretty different from what we'd usually see yet also clearly go together. This is a degree of work and imagination that doesn't seem to come up very often in modern SF shows, which generally look far more normal and conventional.